DAT

Direct antiglobulin test, see Antiglobulin test.

antiglobulin test

A test for the presence in human blood of antibodies. The antibodies present in the blood do not, themselves, cause agglutination. It is the addition of an antibody made in animals (antiglobulin) that stimulates red blood cell clumping. The direct antiglobulin test (DAT) is used to diagnose autoimmune hemolytic anemia and hemolytic disease of the newborn. The indirect antiglobulin test (IAT), or Coombs' test, is used to identify blood types. Synonym: Coombs' test

direct antiglobulin test

Abbreviation: DAT

A laboratory test for the presence of complement or an antibody that is bound to a patient's red blood cells (RBCs). The test is used in patients with autoimmune hemolytic anemia, hemolytic disease of the newborn, and transfusion reactions. After the patient's RBCs are washed to remove unbound antibodies, they are mixed with antihuman globulin serum containing polyvalent antibodies that bind with the antibody or complement on the RBCs and cause them to agglutinate (clump). Monoclonal antibodies can be used to identify the specific class of antibody or complement component causing RBC destruction. See: Coombs' test

direct antiglobulin test

Abbreviation: DAT

A laboratory test for the presence of complement or an antibody that is bound to a patient's red blood cells (RBCs). The test is used in patients with autoimmune hemolytic anemia, hemolytic disease of the newborn, and transfusion reactions. After the patient's RBCs are washed to remove unbound antibodies, they are mixed with antihuman globulin serum containing polyvalent antibodies that bind with the antibody or complement on the RBCs and cause them to agglutinate (clump). Monoclonal antibodies can be used to identify the specific class of antibody or complement component causing RBC destruction. See: Coombs' test

dementia

(di-men'cha) [L. dementia, madness]

A progressive, irreversible decline in mental function, marked by memory impairment and, often, deficits in reasoning, judgment, abstract thought, registration, comprehension, learning, task execution, and use of language. The cognitive impairments diminish a person's social, occupational, and intellectual abilities. In the U.S., 4.5 million people are afflicted by dementia. The prevalence is esp. high in the very elderly: about 20% to 40% of those over 85 are demented. Dementia is somewhat more common in women than in men. It must be distinguished by careful clinical examination from delirium, psychosis, depression, and the effects of medications. See: Alzheimer disease; Huntington chorea; Parkinson disease; table

Symptoms

The onset of primary dementia may be slow, taking months or years. Memory deficits, impaired abstract thinking, poor judgment, and clouding of consciousness and orientation are not present until the terminal stages; depression, agitation, sleeplessness, and paranoid ideation may be present. Patients become dependent for activities of daily living and typically die from complications of immobility in the terminal stage.

Treatment

Some medications, e.g., donepezil, nemantidine, and tacrine, improve cognitive function in some patients.

Patient care

Demented patients deserve respectful and dignified care at all stages of their disease. Caregivers assist the demented with activities of daily living and with the cognitive and behavioral changes that accompany the disease. A variety of nursing interventions may reduce the risk of inadvertently precipitating behavioral symptoms. Health care professionals should reinforce the patient's abilities and successes rather than disabilities and failures. Caregivers can help the patient make optimal use of his or her abilities by reducing the adverse effects of other health conditions, sensory impairments, and cognitive defects while maximizing social and environmental factors that support functional capacity. Daily routines should be adjusted to focus on the person rather than the task, e.g., the comfort of bathing rather than the perceived need to bathe in a certain way at a certain time.

Interaction and communication strategies should be adjusted to ensure that the message delivered is the one perceived (obtain attention, make eye contact, speak directly to the individual, match nonverbal communication and gestures to the message, slow the pace of speech, use declarative sentences, use nouns instead of pronouns). Commands including the word “don’t” and questions beginning with “why” should be avoided. Tasks should be broken down into manageable steps. Reassurance and encouragement are provided to assist the patient to act more independently. Reality grounding is not necessary for such a patient; thus, if the patient asks to see his mother (who is dead), reminding him of her death may reinforce the pain of that loss. It may be better to redirect the conversation, asking the patient to talk about his mother, instead. Written agreements and reminders may not be as useful as they would be in the care of other patients, for a demented patient may not remember what has been negotiated and agreed upon in the past. The patient’s environment should be adjusted to provide needed safety. Finding the correct balance between doing too much or too little may be difficult for the caregiver, who should recognize that the balance may shift day to day and that patience and flexibility are more helpful. Caregivers must be aware that the patient will have moments of lucidity, which should be treasured but not considered evidence that the patient is exaggerating or feigning his or her disease to obtain attention. Family members who provide care must be aware that they, too, have emotional needs and can become angry, frustrated, and impatient and that they need help to learn to forgive themselves as well as the loved one they are caring for. Finally, such caregivers must learn how to accept help and should not fear to admit that they cannot carry the burden of care by themselves.

alcoholic dementia

dementia of the Alzheimer type

apoplectic dementia

Sudden loss of cognitive or intellectual function as a result of a large or bloody stroke or a brain tumor.

Binswanger dementia

Binswanger disease.

dialysis dementia

A neurological disturbance in patients who have been on dialysis for several years. There are speech difficulties, myoclonus, dementia, seizures, and, eventually, death. The causative agent is presumed to be aluminum in the dialysate.

epileptic dementia

An infrequent complication of epilepsy, presumed to result from injury to neurons during uncontrolled seizures.

frontotemporal dementia

A general term for any of four types of dementia: 1. frontotemporal lobar degeneration; 2. Pick’s disease; 3. primary progressive aphasia; or 4. semantic dementia. Symptoms include personality changes, apathy, compulsive or repetitive behavior, lack of social inhibition, and deterioration in language use.

Heller dementia

HIV-associated dementia

dementia with Lewy bodies

A common neurodegenerative disease characterized by gradual and progressive loss of intellectual abilities combined with a movement disorder that resembles Parkinson disease. Those affected often have marked fluctuations in their ability to stay alert and awake and also visual hallucinations. The disease is characterized pathologically by deposits of Lewy bodies. The dementia is treated symptomatically.

mixed dementia

Dementia in which elements of both Alzheimer disease and vascular dementia are found.

multi-infarct dementia

Dementia resulting from multiple small strokes. After Alzheimer disease, it is the most common form of dementia in the U.S. It has a distinctive natural history. Unlike Alzheimer disease, which develops insidiously, the cognitive deficits of multi-infarct dementia appear suddenly, in stepwise fashion. The disease is rare before middle age and is most common in patients with hypertension, diabetes mellitus, or other risk factors for generalized atherosclerosis. Brain imaging in patients with this form of dementia shows multiple lacunar infarctions. Synonym: vascular dementia

paralytic dementia

An obsolete term for tertiary syphilis.

dementia paralytica

An obsolete term for tertiary syphilis.

postfebrile dementia

Dementia following a severe febrile illness.

presenile dementia

Dementia beginning in middle age, usually resulting from cerebral arteriosclerosis or Alzheimer disease. The symptoms are apathy, loss of memory, and disturbances of speech and gait.

primary dementia

Dementia associated with Alzheimer disease.

dementia pugilistica

Traumatic dementia, i.e., encephalopathy or an organic brain syndrome caused by closed head injury. It is sometimes referred to colloquially as “boxer's brain.”

semantic dementia

Any of a group of brain disorders marked by nearly complete losses in the understanding of word meanings, spelling, and the identification or recognition of facts, faces, or objects. The disease is marked pathologically by local atrophy in the neocortex of the temporal lobe of the brain.

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